Military history of Nepal

Pro- and anti-British factions in certain areas of Nepal had been vying for power since 1816. In 1846 the pro-British army leader Sir Jung Bahadur (1816–77) of the Rana family finally overthrew the Nepalese government and declared himself the prime minister. Like many dictatorships, Jung Bahadur's office was passed on through hereditary rather than valid elections. Jung Bahadur launched a successful military campaign in 1854 with the aim of invading Tibet. In 1856 Tibet signed a peace treaty which granted diplomatic and commercial rights to Nepal on the condition that Tibet continue to pay a yearly "tribute" to the Nepalese government.
Relations with Great Britain and World War I
Nepal aided Great Britain during the Sepoy Mutiny (1857–59) and during World War I. The British government in gratitude for Nepal's assistance declared the independence and sovereignty of Nepal to be genuine by the terms of a treaty concluded in 1923.
On September 4th, 1939 Nepal declared war on Germany in solidarity with the Allied Forces. Due to the undemocratic nature of Nepal's government, their national validity and respect was maintained by continuing healthy relations with Great Britain by rendering much needed military assistance as they had in World War I and the Sepoy Mutiny. Twelve regiments of Gurkha soldiers from Nepal were sent to fight in the British Indian Army. Although Britain has been recruiting Gurkha soldiers from Nepal since the 19th century, no effort was made to develop a centralized recruit-training system in the Brigade of Gurkhas throughout the pre Second World War era. As a result, recruiting training was conducted at the various Gurkha regimental training centres in India. After the end of the war, Nepal also established good diplomatic relations with the United States in 1948.